Description
In the Linux kernel, the following vulnerability has been resolved:
smb: client: require a full NFS mode SID before reading mode bits
parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS mode SID and reads sid.sub_auth[2] to recover the mode bits.
That assumes the ACE carries three subauthorities, but compare_sids() only compares min(a, b) subauthorities. A malicious server can return an ACE with num_subauth = 2 and sub_auth[] = {88, 3}, which still matches sid_unix_NFS_mode and then drives the sub_auth[2] read four bytes past the end of the ACE.
Require num_subauth >= 3 before treating the ACE as an NFS mode SID. This keeps the fix local to the special-SID mode path without changing compare_sids() semantics for the rest of cifsacl.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:HWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | >= e2f8fbfb8d09c06decde162090fac3ee220aa280, < 23b54d6cc3ef30a51d984dc74364f24039ae2ecb; >= e2f8fbfb8d09c06decde162090fac3ee220aa280, < 1592a6cd6f653f2d24572a6976c7a775b19f4940; >= e2f8fbfb8d09c06decde162090fac3ee220aa280, < 8bd4cad3f458d11650d51c2d24b03fb1770ae6cc; >= e2f8fbfb8d09c06decde162090fac3ee220aa280, < b53b8e98c23310294fc45fc686db5ee860311896; >= e2f8fbfb8d09c06decde162090fac3ee220aa280, < c8eef12af1cc73031639ea7cf16e0b10e2536b0b; >= e2f8fbfb8d09c06decde162090fac3ee220aa280, < 38a69f08ee82c450d3e4168707fff2e317dc3ff7; >= e2f8fbfb8d09c06decde162090fac3ee220aa280, < f8488c07bea2431ee12a6067d736578064fa46b4; >= e2f8fbfb8d09c06decde162090fac3ee220aa280, < 2757ad3e4b6f9e0fed4c7739594e702abc5cab21 |
| Linux | Linux | 5.4 |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | < * |
References
- https://git.kernel.org/stable/c/1592a6cd6f653f2d24572a6976c7a775b19f4940
- https://git.kernel.org/stable/c/23b54d6cc3ef30a51d984dc74364f24039ae2ecb
- https://git.kernel.org/stable/c/2757ad3e4b6f9e0fed4c7739594e702abc5cab21Patch
- https://git.kernel.org/stable/c/38a69f08ee82c450d3e4168707fff2e317dc3ff7Patch
- https://git.kernel.org/stable/c/8bd4cad3f458d11650d51c2d24b03fb1770ae6cc
- https://git.kernel.org/stable/c/b53b8e98c23310294fc45fc686db5ee860311896Patch
- https://git.kernel.org/stable/c/c8eef12af1cc73031639ea7cf16e0b10e2536b0bPatch
- https://git.kernel.org/stable/c/f8488c07bea2431ee12a6067d736578064fa46b4Patch
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
Timeline
- Published
- May 8, 2026
- Last modified
- Nov 11, 2026
- NVD status
- Modified